Typical electronic devices, such as, for examples, multi-functional peripherals (MFPs) that can print documents and images and other image forming apparatuses, can supply electric power to various units in the electronic device.
In a typical image forming apparatus operable in an energy-saving mode in which an energy-saving state is enabled, each function is managed in correlation with parts and components necessary for executing the function. When the image forming apparatus returns from the energy-saving state, information about parts and components corresponding to a preset function is read and electric power is supplied to the parts and components indicated in the read information. However, a typical electronic device cannot individually control power supply to each constituent unit if the main power source is turned on in a state in which the user has not selected any function. Then, the electronic device enters a normal activation state in which electric power is supplied to all units. In this situation, power-saving efficiency is lowered because electric power is supplied to, for example, a fixing part as well.